EP1427695A1

EP1427695A1 - Method of producing nitrile compounds

Info

Publication number: EP1427695A1
Application number: EP02779637A
Authority: EP
Inventors: Jean-Marie Basset; Yves Chauvin; Jean-Christophe Galland; Gerry Niccolai; Christine Valerio; Christophe Vallee
Original assignee: Rhodia Polyamide Intermediates SAS
Current assignee: Rhodia Operations SAS
Priority date: 2001-09-18
Filing date: 2002-09-17
Publication date: 2004-06-16
Also published as: CN1564807A; RU2004111655A; CN100455562C; FR2829763B1; US8039660B2; US20090247780A1; WO2003024919A1; FR2829763A1; US20040260112A1; JP4166155B2; JP2005503410A; KR20040068537A; RU2265591C2

Abstract

The invention relates to a method of producing nitrile compounds from unsaturated organic compounds by reaction with hydrogen cyanide. More specifically, the invention relates to the production of nitrile compounds that are used to synthesise adiponitrile which is an important chemical intermediate for the production of large chemical compounds, such as hexamethylene diamene and epsilon -caprolactam. Moreover, the invention relates to a method of producing organic compounds comprising at least one nitrile function by means of a hydrocyanation reaction between the hydrogen cyanide and an organic compound having at least one ethylenic unsaturation. Said reaction is carried out in the presence of a catalytic system comprising a metallic element which is selected from the group containing nickel, platinum, palladium and an organophosphorous ligand. In addition, the reaction medium contains an ionic liquid which is in liquid state at least at the temperature at which the hydrocyanation reaction is carried out.

Description

PROCESS FOR MANUFACTURING NITRILE COMPOUNDS

The present invention relates to the manufacture of nitrile compounds from unsaturated organic compounds by reaction with hydrogen cyanide. It relates more particularly to the manufacture of nitrile compounds used for the synthesis of adiponitrile, an important chemical intermediate for the manufacture of large chemical compounds such as hexamethylene diamine and ε-caprolactam. These last two compounds are used, in particular, in the manufacture of polymers such as polyamides and more particularly polyamides 6 and 6-6, or other polymers such as polyurethanes.

Several methods of manufacturing nitrile compounds have been proposed. Among these, the direct hydrocyanation of an olefin or polyolefin such as, for example, 1, 3-butadiene by reaction with hydrogen cyanide is a process developed industrially and which is the subject of numerous patents or publications. This process consists, roughly, in a first step to carry out the addition of a molecule of HCN on an ethylenic unsaturation to obtain an unsaturated nitrile compound. In fact, this step leads to the production of many isomers of unsaturated nitriles. The addition of a new HCN molecule leads, in a next step to a polynitrile, for example, to a dinitrile such as adiponitrile when the starting olefin is 1, 3-butadiene.

To avoid and limit the production of by-products that do not have significant use properties, the process comprises, after the first hydrocyanation step, a step called “isomerization step” consisting in transforming the major part of the branched nitrile isomers in linear nitrile isomers such as, in the case of the hydrocyanation of butadiene, in 3- and 4-pentenenitriles.

These reactions are generally carried out in the liquid phase in the presence of a catalyst based on a metal, most often nickel present in the form of a complex with an organic ligand. This reaction can be carried out in a homogeneous medium, the catalyst being soluble in the hydrocyanation medium, in particular in olefin or nitriles or in a third solvent. It can also be carried out with a medium having several liquid phases, the catalyst being soluble in one of the phases, more precisely in the phase formed by a third polar solvent generally water, phase distinct from that formed by the olefin and the nitriles. , at least at room temperature. This latter embodiment makes it possible to extract and recover the catalyst more easily and therefore to obtain nitrile compounds containing less impurities supplied by the catalyst. These catalytic systems have been described in numerous patents and several classes of ligands have been studied. Generally, ligands are organophosphorus compounds such as phosphites, phosphinites, phosphonites or phosphines. They can be monodentates or polydentates. In the case of processes in a two-phase medium, these organophosphorus ligands advantageously comprise one or more ionizable groups such as the sulfonate, phosphate, carboxylate or ammonium groups, for example to make them soluble in the polar phase.

As an example of description of these processes, mention may be made of US Pat. No. 3,496,217 which describes the synthesis of adiponitrile by reaction of hydrogen cyanide with butadiene in the presence of a catalyst based on nickel complexed with a ligand such than triaryl phosphite. This reaction is carried out with a cataiysis in a single-phase medium.

As for French Patent No. 2,338,253, it also describes a process for the synthesis of adiponitrile by hydrocyanation of butadiene. The reaction is carried out in a two-phase liquid medium, the catalyst being contained in an aqueous phase. This process makes it possible to recover adiponitrile in the organic phase free of catalyst and therefore of metal. The catalyst described is also a catalyst based on a metal such as nickel associated with a phosphine type ligand. However, this ligand comprises sulfonate radicals making it possible to make the catalyst soluble or dispersible in water. Furthermore, it is also known to combine the nickel-based catalyst with promoters such as Lewis acids, such as, for example, zinc chloride, triphenylborane for the hydrocyanation of an unsaturated nitrile compound.

Constant research is undertaken to improve the performance of the synthesis of nitriles by hydrocyanation, either by development of new catalytic systems, or by modification of the reaction conditions and compositions of the hydrocyanation medium.

Among the latest patents published, US Pat. No. 6,169,198 describes the use of new metallocene-phosphorus type ligands. Likewise, US Pat. No. 5,773,637 describes the use, as Lewis acid, of the perfluoroalkylsulfonate compounds. One of the aims of the present invention is to propose a new process for the manufacture of nitriles by hydrocyanation of an olefin by reaction with hydrogen cyanide, making it possible to obtain high yields and selectivities of linear nitriles as well as system stability. improved catalytic.

To this end, the invention provides a process for manufacturing organic compounds comprising at least one nitrile function by implementing a hydrocyanation reaction between hydrogen cyanide and an organic compound comprising at least one ethylenic unsaturation. This last compound will be called for more than simplicity in the present invention, an olefin or poiyolefin when it comprises several ethylenic unsaturations. However, this designation "olefin" should not be interpreted as a limitation of the organic compounds suitable for the invention to hydrocarbons, but it also relates to organic compounds comprising at least one ethylenic unsaturation, and which may comprise atoms other than carbon and hydrogen or mixtures of hydrocarbons such as the mixture obtained by distillation of petroleum called in the field of hydrocarbons cut C4. This cut is advantageously treated to remove or transform the impurities such as the compounds comprising an acetylenic unsaturation, for example by hydrogenation as described in US Pat. No. 6,197,992. We will consider as an "olefin" within the meaning of the present invention, a compound comprising an unsaturation and a nitrile function such as for example the unsaturated nitrile compounds obtained by the reaction of HCN on a polyolefin.

According to a characteristic of the invention, the reaction is carried out in the presence of a catalytic system comprising a metallic element chosen from the group comprising nickel, platinum, palladium and an organophosphorus ligand, the reaction medium comprising, in addition an ionic liquid at least in the liquid state at the temperature for carrying out the hydrocyanation reaction.

In a first embodiment, the ionic liquid and the compound to be hydrocyanated are completely miscible, at least at the reaction temperature. The hydrocyanation reaction is carried out in a homogeneous or monophasic medium. In a second embodiment, the ionic liquid and the compound to be hydrocyanated are not or only partially miscible at the reaction temperature. The reaction is carried out in a non-homogeneous or biphasic medium. In this embodiment, the catalytic system is advantageously soluble in the ionic liquid.

In these two embodiments, it is possible to add a slightly polar solvent. This slightly polar solvent can be added at the start of the reaction, but also can be used only after the end of the reaction to thus promote the separation of hydrocyanated products and ionic liquid in particular to allow the extraction of the catalytic system. In fact, the function of the slightly polar solvent is to render the ionic liquid insoluble in the phase constituted by said solvent, the untransformed olefin and the nitrile compounds formed.

Whatever the embodiment, it is preferable that the catalytic system is at least partially miscible in the ionic liquid. Advantageously, this miscibility can be obtained by the presence of at least one ionizable group in the molecule of the organophosphorus ligand. As ionizable groups, mention may be made of anionic type groups such as sulfonate, sulfinate, phosphonate, phosphinate, carboxylate, sulfinate, or cationic type such as guanidinium, ammonium, pyridinium, imidazolium, phosphonium, sulfonium, for example. The number and the nature of these ionic groups are preferably chosen to obtain a solubility of the ligand in the ionic liquid. It may be advantageous for the nature of the ionizable group to be identical to that of the anion or of the cation associated with the ionic liquid.

The catalytic systems suitable for the invention are those which preferably comprise the element nickel in the zero oxidation state or a complex with organophosphorus ligands which can comprise several ionizable groups described above or more generally the compounds containing phosphorus capable of giving a coordination compound with the transition metals and more particularly the catalytic metals mentioned above, in particular with nickel. These compounds can be mono, bi or polydentate and have a hydrophobic or hydrophilic character. These compounds have been described in numerous patents relating to the hydrocyanation of butadiene and belong to several classes including in particular organophosphites, organophosphonites, organophosphinites, organophosphines.

Such catalytic systems and their preparation processes are described, for example, in French patents 2,338,253, 2,710,909, 2,711,987, 2,739,378, 2,778,915. As examples of organic phosphorus compounds suitable for the invention, mention may be made of alkylphosphines, aryiphosphines, alkylarylphosphines, alkylphosphites, arylphosphites, alkylarylphosphites, alkyiphosphinites, arylphosphinites, alkylarylphosphinites, alkyiphosphonites, arylphosphonites, alkylarylphosphonites, the organic half of which is preferably up to 36 carbon atoms, substituted by one or more ionic groups described above.

Examples of compounds that may be mentioned are tributylphosphine, dimethyl-n-octylphosphine, tricyclohexylphosphine, triphenylphosphine, tolylphosphine, tris (p-methoxyphenyl) phosphine, diphenylethylphosphine, dimethylphenylphosphine, 1, 4-phenyl-diphenyl , triethylphosphite, diphenylphosphite, said compounds preferably comprising at least one ionic group described above. As examples of such compounds, mention may be made of sodium triphenylphosphinomonometasuifonate (TPPMS.Na), 2- (5-sodiocarboxyfuryl) diphenylphosphine, (3-sodiosulfinatophenyl) diphenylphosphine. As described in the patents cited above, the catalyst can be prepared before its introduction into the medium, ie in situ. For this, use is preferably made of compounds of the metals forming the catalytic element, such as nickel, which are added in a medium in which the organophosphorus ligand is also soluble. Such a medium may be the ionic liquid. The catalytic system thus formed is added to the hydrocyanation medium. Among the aforementioned compounds, the preferred compounds are those of nickel, there may be mentioned as non-limiting examples:

- compounds in which the nickel is at zero oxidation state such as potassium tetracyanonickelate K4 [Ni (CN) 4], bis (acrylonitrile) zero nickel, bis (cyclooctadiene-1, 5) 2 nickel and derivatives containing Group Va ligands such as tetrakis (triphenylphosphine) zero nickel;

- nickel compounds with a degree of oxidation greater than zero such as carboxylates (in particular acetate), carbonate, bicarbonate, borate, bromide, chloride, citrate, thiocyanate, cyanide, formate, hydroxide, hydrophosphite, phosphite, phosphate and derivatives , iodide, nitrate, sulfate, sulfite, aryl- and alkyl-sulfonates, allyl, acetylacetonate. It is not necessary for the nickel compound itself to be soluble in the preparation medium such as the ionic liquid. Indeed, it is sufficient that the complex is soluble, that is to say that the solubilization of nickel occurs during the addition of the ligand in the ionic liquid.

When the nickel compound used corresponds to an oxidation state of nickel greater than 0, a reducing agent for nickel reacting preferentially with the latter under the reaction conditions is added to the reaction medium. This reducing agent can be organic or mineral or hydrogen. As nonlimiting examples, mention may be made of Zn powder, magnesium, BH4K, BH4Na and borohydrides preferably soluble in water. This reducing agent is added in an amount such that the number of redox equivalents is between 1 and 10. However, values less than 1 and greater than 10 are not excluded.

When the nickel compound used corresponds to the oxidation state 0 of nickel, it is also possible to add a reducing agent of the type of those mentioned above, but this addition is not imperative.

When using an iron compound, the same reducers are suitable. In the case of palladium, the reducing agents can also be elements of the reaction medium (phosphine, solvent, olefin).

According to the invention, the reaction medium comprises an ionic liquid. This ionic liquid is an ionic compound whose cation is of onium type having at least one heteroatom such as N, P, S carrying the positive charge in conjugation with an aromatic cycle with 5 or 6 elements and an anion. Such compounds are for example described in the article by Yves Chauvin and Hélène Olivier - Bourbigou entitled "Non aqueous ionic liquids as reaction solvents" published in Chemtech 12, 1995, p 66, the article by T. Welton published in Chem. Rev. 1999, p 2071 or patents such as patent Ep 971 854. According to a preferred characteristic of the invention, the ionic liquid comprises at least one cation chosen from the group comprising the structures tetraalkylammonium, N-alkylimidazolium, N-alkylpyridinium, N- aikylpicolinium, N-alkyltriazolium, N- alkylfluoropyrazolium, N-pyrrolidinium, alkylsulfonium, tetraalkylphosphonium, alkyloxonium. As examples of preferred cations of the invention, mention may be made of aikylimidazoliums such as 1,3-dimethylimidazolium, 1-butyl-2,3-dimethyl imidazolium, 1-butyl-3-methylimidazolium or 1,2, 3-triméthylimidazoiium.

As preferred anions of the invention, there may be mentioned an anion chosen from halides, nitrate, phosphate, hydrosulfate, perfluoroalkyisulfonates, bis (perfluoroalkylsulfonyl) amides, bis (fluorosulfonyl) amide, bis (fluorophosphoryl ) amide, tris (perfluoroalkylsulfonyl) methylides, boron, aluminum, gallium, iron tetrahalides, phosphorus, arsenic and antimony hexahalides, zinc and tin trihalides, dihalides copper. Preferred anions of the invention are Br ^"f, ^BF" _4, PF ^_"6, SbF _^6", IAAH _4l ZnCl ^_"3,

SnCfs, (CF ₃ SO ₂ ) ₂ N ^" .-

The ionic liquid to be suitable with the process of the invention must be at least in the liquid state at the temperature for carrying out the hydrocyanation reaction. However, ionic liquids which are in the liquid state at a temperature below 100 ° C. are preferred because they allow better separation and extraction of the catalyst from the reaction medium in the case of a two-phase system.

In addition, according to the embodiment of the invention (mono or biphasic system), the ionic liquid which becomes miscible or at least partially miscible in the reaction medium only at the temperature of the implementation of the hydrocyanation reaction, or in the vicinity thereof, is entirely compatible for carrying out the invention.

In the embodiment in a two-phase medium, the immiscibility of the ionic liquid, at least at low temperature, is preferably obtained by adding a slightly polar solvent to the reaction medium. This solvent dissolves the olefins to be hydrocyanated as well as the nitriles produced and makes the ionic liquid insoluble in the olefins and nitriles produced. As slightly polar solvent, mention may be made of saturated hydrocarbons such as hexane, heptane, octane, toluene, ethers such as diethyl ether, diisopropyl ether, methylisobutyl ether.

The conditions for carrying out the hydrocyanation reaction are described below, by way of example. Thus, the quantity used of nickel compound or of another transition metal is chosen to obtain a concentration in mole of transition metal per mole of organic compounds to be hydrocyanated or isomerized between 10 ^~ 4 and 1, and preferably " between 0.005 and 0.5 mole of nickel or of the other transition metal used. The amount of ligand used to form the catalyst is chosen so that the number of moles of this compound, based on 1 mole of transition metal, is between 0.5 and 50 and preferably between 2 and 10.

The hydrocyanation reaction is generally carried out at a temperature between 10 ° C and 200 ° C and preferably between 30 ° C and 120 ° C. The process of the invention can be carried out continuously or discontinuously.

The hydrogen cyanide used can be prepared from metallic cyanides, in particular sodium cyanide, or cyanhydrins, such as acetone cyanohydrin or by any other known synthesis process. The hydrogen cyanide is introduced into the reactor in gaseous form or in liquid form. It can also be previously dissolved in an organic solvent. In the context of a discontinuous implementation, it is in practice possible to charge into a reactor, previously purged using an inert gas (such as nitrogen, argon), either a solution containing all or part of the various constituents, the transition metal compound, any reducing agents and solvents, or separately said constituents. Generally the reactor is then brought to the chosen temperature, then the compound to be hydrocyanated is introduced. The hydrogen cyanide is then itself introduced, preferably continuously and regularly.

When the reaction is complete, the reaction mixture is withdrawn after cooling and the reaction products are isolated, for example, by separation of the phase containing the catalytic system and of the phase formed by the weakly or non-polar solvent, the hydrocyanated products and those which have not been transformed in the case of a two-phase system. The products of this last phase can be separated by distillation, for example. In the case of a single-phase system, other separation means can be used such as, for example, distillation, liquid / liquid extraction. In the case where the product to be hydrocyanated is an unsaturated compound comprising a nitrile function, it is advantageous to use with the catalytic system a cocatalyst consisting of at least one Lewis acid.

This reaction consists in particular in converting the ethylenically unsaturated aliphatic nitriles, in particular the linear pentenenitriles such as pentene-3-nitrile, pentene-4-nitrile and their mixtures obtained by hydrocyanation of butadiene into dinitriles more precisely into adiponitrile.

These pentenenitriles may contain quantities, generally in the minority, of other compounds, such as methyl-2-butene-3-nitrite, methyl-2-butene-2-nitrile, pentene-2-nitrile, valeronitria, adiponitrile, methyl-2-glutaronitrile, ethyl-2-succinonitrile or butadiene, originating from the previous hydrocyanation reaction of butadiene and or from the isomerization of methyl-2-butene-3-nitrile into pentenenitriles.

The Lewis acid used as cocatalyst allows in particular, in the case of the hydrocyanation of aliphatic nitriles with ethylenic unsaturation, to improve the linearity of the dinitriies obtained, that is to say the percentage of linear dinitriles relative to the all of the dinitriles formed, and / or to increase the activity and the lifetime of the catalyst.

By Lewis acid is meant in the present text, according to the usual definition, compounds that accept electronic doublets. It is possible to use in particular the Lewis acids cited in the work edited by G.A. OLAH "Friedel-Crafts and related Reactions", volume I, pages 191 to 197 (1963). The Lewis acids which can be used as cocatalysts in the present process are chosen from the compounds of the elements of groups Ib, llb, llla, lllb, IVa, IVb, Va, Vb, Vlb, Vllb and VIII of the periodic table elements. These compounds are most often salts, in particular halides, such as chlorides or bromides, sulfates, sulfonates, halogenosulfonates, perhaloalkylsulfonates, in particular fluoroalkylsulfonates or perfluoroalkylsulfonates, carboxylates and phosphates, bis (perfluorakylsulfonyl) amidides, trisyl).

By way of nonlimiting examples of such Lewis acids, mention may be made of zinc chloride, zinc bromide, zinc iodide, manganese chloride, manganese bromide, cadmium chloride, bromide cadmium, stannous chloride, stannous bromide, stannous sulfate, stannous tartrate, indium trifluoromethylsulfonate, chlorides or bromides of rare earth elements like lanthanum, cerium, praseodymium, neodymium, samarium, l europium, gadolinium, terbium, dysprosium, hafnium, erbium, thallium, ytterbium and lutetium, cobalt chloride, ferrous chloride, yttrium chloride. Organometallic compounds such as triphenylborane and titanium diisopropylate can also be used as the Lewis acid. It is of course possible to use mixtures of several Lewis acids. Among the Lewis acids, zinc chloride, zinc bromide, stannous chloride, stannous bromide, triphenylborane and zinc chloride / stannous chloride mixtures are particularly preferred.

Preferably, a Lewis acid having an anion identical or of the same nature as the anion of the ionic liquid, for example zinc chloride, will be chosen, when the ionic liquid comprises, as an anion ZnCI ₃ , aluminum chloride when the anion of the ionic liquid is the AICI ₄ anion, the lanthanum tris (bistrifluoromethylsufonylamide) when the ionic medium consists of the bistrifluoromethylsulfonylamide anion, the tri (trifluoromethylsuifonate) of neodymium when the ion of the ionic medium is the trifluoromethylsulfonate anion. We can also use an ionic liquid consisting of a mixture of polynuclear anions such as Pennion Zn ₂ CI ₅ ^" and ZnCI ₃ ^" , or AI ₂ C! ₇ ^' and AICI ₄ ^" .

In a preferred embodiment of the invention, the Lewis acid will be provided by the anion of the ionic liquid. This ionic liquid itself brings the cocatalysis effect into the medium.

The Lewis acid cocatalyst used generally represents from 0.01 to 50 mole per mole of transition metal compound, more particularly of nickel compound, and preferably from 1 to 10 mole per mole.

It is also possible under the conditions of the hydrocyanation process of the present invention, and more particularly in the presence of an ionic liquid, to carry out, in the absence of hydrogen cyanide, the isomerization of methyl! -2-butene- 3-nitrile to pentenenitriles, and more generally unsaturated nitriles branched into linear unsaturated nitriles.

The methyl-2-butene-3-nitrile subjected to the isomerization according to the invention can be used alone or as a mixture with other compounds.

Thus, methyl-2-butene-3-nitrile can be used in admixture with methyl-2-butene-2-nitrile, pentene-4-nitrile, pentene-3-nitriie, pentene-2-nitrile, butadiene, adiponitrile, methyl-2-glutaroronitrile, rethyl-2-succinonitriie or vaiéronitriie.

It is particularly advantageous to treat the reaction mixture originating from the hydrocyanation of butadiene with HCN according to the conditions of the invention, that is to say in the presence of an ionic liquid. In the context of this preferred variant, the catalytic system already being present for the hydrocyanation reaction of butadiene, it suffices to stop any introduction of hydrogen cyanide, to allow the isomerization reaction to take place.

It is possible, if necessary, in this variant to make a slight sweeping of the reactor using an inert gas such as nitrogen or argon for example, in order to remove the hydrocyanic acid which could still be present.

The isomerization reaction is generally carried out at a temperature of 10 ° C to 200 ° C and preferably from 60 ° C to 120 ° C.

In the preferred case of isomerization immediately following the hydrocyanation reaction of butadiene, it will be advantageous to operate at the temperature at which the hydrocyanation has been carried out.

As for the hydrocyanation process for ethylenically unsaturated compounds, the catalytic system used for isomerization can be prepared before its introduction into the reaction zone. It is also possible to prepare the catalytic system "in situ" by simple mixing of these various constituents. The amount of compound of the transition metal and more particularly of nickel used, as well as the amount of ligand are the same as for the hydrocyanation reaction.

However, the preparation of dinitrile compounds by hydrocyanation of an olefin such as butadiene can be carried out using a reaction system in accordance with the invention for the stages of formation of the unsaturated nitriles and the stage of isomerization above, the reaction hydrocyanation of the nitriles unsaturated into dinitriles which can be used with a reaction system according to the invention or any other catalytic system already known for this reaction.

Likewise, the hydrocyanation reaction of the olefin to unsaturated nitriles and the isomerization of these can be carried out with a reaction system different from that of the invention, the step of hydrocyanation of the unsaturated nitriles into dinitriles being implemented with a reaction system according to the invention.

The examples given below only for information, will illustrate the invention and its advantages.

PREPARATION OF IONIC LIQUIDS

Synthesis of 1-butyl-2,3-dimethylimidazolium bis-trifluoromethylsulfonylamide (BMMrTF, N ")

40.50 g (0.215 mol) of 1-butyl-2,3-dimethylimidazolium chloride are dissolved in 300 ml of distilled water. 61.62 g (0.215 mol) of lithium bis-trifluoromethylsulfonylamide are added and the mixture is stirred under argon for 72 hours at temperature room. A two-phase system is formed. After extraction with 250 ml of dichloromethane, the organic phase is washed with 800 ml of water and then concentrated. The compound is in the form of a slightly pink liquid which is purified by chromatography on a column of neutral alumina (eluent: dichloromethane). It is then concentrated, taken up in acetonitrile in the presence of activated carbon and filtered. After drying for several hours at 60 ° C., the compound is obtained in the form of a colorless liquid (83.78 g, 90%). The structure of this product: CnHι ₇ N ₃ S ₂ 0 F ₆ is confirmed by NMR spectral analysis.

Synthesis of 1-butyl-3-methylimidazolium bis-trifluoromethylsulfonylamide

(BMΓTF _; N-)

41.92 g (0.240 mol) of 1-butyl-3-methylimidazolium chloride are dissolved in 300 ml of distilled water. 69.46 g (0.242 mol) of lithium bis-trifluoromethylsulfonylamide are added and the mixture is stirred under argon for 90 hours at room temperature. A two-phase system is formed. After extraction with 250 ml of dichloromethane, the organic phase is washed with 800 ml of water and then concentrated. The compound is in the form of a slightly pink liquid which is purified by chromatography on a column of neutral alumina (eluent: dichloromethane). It is then concentrated, taken up in acetonitrile in the presence of activated carbon and filtered. After drying for several hours at 60 ° C., the compound is obtained in the form of a colorless liquid (81.47 g). Its structure C ₁₀ H ₁₅ N ₃ S ₂ OF ₆ was confirmed by NMR analysis.

. Synthesis of 1-butyl-2,3-dimethylimidazolium hexafluorophosphate (BMMΓPF _S -)

33.37 g (0.200 me) of sodium hexafluorophosphate and 37.50 g (0.199 mol) of 1-butyl-2,3-dimethylimida∑olium chloride are dissolved in 150 ml of acetone. After vigorous stirring for 72 hours at room temperature under argon, the solution is filtered through celite and then concentrated. After chromatography on an alumina column (eluent: dichloromethane), the salt is taken up in acetonitrile in the presence of activated carbon and filtered. The concentration of the solution gives 50.41 g (0.170 mol, 85%) of a white solid. The structure of this product C ₉ Hι ₇ N ₂ PF _s is confirmed by NMR spectral analysis.

In the examples below, the abbreviations used have the following meanings: cod: 1,5-cyclooctadiene. eq: equivalent.

2M3BN: 2-methyl-3-butenenitrile.

2M2BN: 2-methyl-2-butenenitrile.

3PN: 3-pentenenitrile. 4PN: 4-pentenenitrile.

3 + 4PN: 3PN + 4PN.

DN: DNA + MGN + ESN

MGN: methylglutaronitrile

ESN: ethylsuccinonitrile TT (Y): transformation rate of the product to be hydrocyanated Y corresponding to the ratio of the number of transformed moles of Y to the number of initial moles of Y.

RR (X): actual yield of compound X corresponding to the ratio of the number of moles formed from X to the maximum number of moles of X.

RT (X): selectivity of compound X corresponding to the ratio of RR (X) to TT (Y). L: Linearity: RT _A dN RTDN

GC: gas chromatography. TPPMS.Na: Sodium triphenylphosphate P (Ph) ₂ PhS0 ₂ Na (3-sodiosulfinatophenyl) diphenylphosphine P (Ph) ₂ FuC0 ₂ Na 2- (5-sodiocarboxyfuryl) diphenylpl osphine BPh ₃ Boron triphenyl ln (CF ₃ S0 ₃ ) ₃ ZnPh ₂ Zn (CF ₃ S0 ₃ ) ₂

ISOMERIZATION OF 2-METHYL-3-BUTENENITRILE (2M3BN) IN LINEAR PENTENENITRILES

The tests were carried out according to the following procedure and in a “Radieys” parallel reactor which allows the simultaneous stirring and reflux of 12 glass tubes called Schlenk tubes.

In a glass tube are introduced successively and under argon: -10 mg (0.036 mmol, 1 equivalent) of Ni (COD) ₂

-66 mg (0.18 mmol, 5 equivalents) TPPMS, Na

-1.5 g of ionic liquid

-400 mg (4.93 mmol, 137 equivalents) of 2M3BN. The solution is stirred for 10 minutes at room temperature, then 1.2 ml of heptane are added to obtain a two-phase reaction medium. The tube is closed, then stirred and heated at 100 ° C for 3 hours with overhead cooling. At the end of the reaction, the tubes are cooled in liquid nitrogen. A known quantity of butyibenzene (approximately 40 mg, to serve as an internal standard in chromatography) is added to the biphasic reaction medium which is diluted and homogenized by the addition of 10 ml of THF. The solution obtained is filtered on a short column of silica and injected by gas chromatography (GC).

In the tests carried out according to the above procedure, the starting materials include 2M3BN and other products. The molar formulation of these products is given in Table I below (the main components are indicated).

Board

The results obtained with different salts are collated in Table 11 below. By way of comparison, a test was carried out with a catalyst based on nickel and a ligand, triphenylphosphine, in single-phase medium.

Table II

(1) comparative test without ionic liquid with the ligand triphenylphosphine. Tests have been carried out without using any solvent such as heptane to obtain a single-phase system. The procedure used is identical to that described above with the exception of the absence of an apoietic solvent. The results obtained are listed in Table III below:

Table III

Hydrocyanation of 3PN into DNA In a glass tube are introduced successively and under argon:

-40 mg (0.145 mmol, 1 equivalent) of Ni (DOC) ₂ -264 mg (0.72 mmol, 5 equivalents) of TPPMS.Na

-1.5 ml of ionic liquid or 2.1 g if the salt is solid at room temperature -400 mg (4.93 mmol, 34 equivalents) of 3PN -1 equivalent of Lewis acid

The tube is closed with a stopper provided with a septum. The reaction mixture is stirred and heated at 70 ° C for 3 hours, during which time the acetone cyanohydrin is slowly added (flow rate 0.12 ml / h, 0.36 ml, 3.95 mmol, 27 equivalents).

At the end of the reaction, 15 ml of acetone are added to the tube, cooled to room temperature. The solution is stirred for 10 minutes, then poured into a bottle containing a known quantity of butylbenzene (approximately 250 mg, to serve as an internal standard in chromatography). The solution is filtered and injected with CPG.

A first series of examples was carried out using different Lewis acids. The results obtained are shown in Table IV below:

Table IV

A second series of examples was carried out using different ionic liquids and ligands. . The results obtained are shown in Table V below:

Table V

Claims

1. Process for manufacturing organic compounds comprising at least one nitrile function by reaction between hydrogen cyanide and an organic compound j comprising at least one ethylenic unsaturation in the presence of a catalyst comprising an element chosen from the group of nickel, platinum , palladium and an organophosphorus ligand, characterized in that the reaction is carried out in the presence of an ionic liquid comprising at least one cation and at least one anion and being liquid at least at the temperature at which the reaction is carried out.

2. Method according to claim 1, characterized in that a slightly polar solvent is added to the reaction medium to form a two-phase system

3. Method according to claim 1 or 2, characterized in that the organophosphorus ligand comprises at least one ionizable function or an ionic group.

4. Method according to claim 1 or 3, characterized in that the ionic liquid comprises at least one cation chosen from the group comprising the structures tetraaikylammonium, N-alkylimidazolium, N-alkylpyridinium, N-alkylpicolinium, N-alkyltriazolium, N-alkylfluoropyrazolium , N-pyrrolidinium, alkylsulfonium, tetraalkylphosphonium, alkyloxonium.

5. Method according to one of claims 1 to 4, characterized in that the ionic liquid comprises at least one anion chosen from the group comprising halides, nitrate, phosphate, hydrosulfate, perfluoroalkylsulfonates, bis

(perfluoroalkylsulfonyl) amides, bis (fluorosulfonyl) amide, bis (fluorophosphoryi) amide, tris (perfluoroalkylsulfonyl) methylides, tetrahalides of boron, aluminum, gallium, iron, hexahalides of phosphorus, arsenic and antimony, zinc and tin trihalides, copper dihalides.

6. Method according to claim 5, characterized in that the anion is chosen from the group comprising Bf, I ^" , BF _4l PF _βl SbF ₆ ^" , AICl ^" _4. ZnCI ^' _3l SnCl ^" ₃ , (CF ₃ S0 ₂ ) ₂ N-.

7. Method according to one of claims 4 to 6, characterized in that the cation is chosen from the group comprising 1, 3-dimethylimidazolium, 1-butyl-2,3-dimethylimidazolium, 1-butyl-3- methylimidazolium or 1,2,3-trimethylimidazolium.

8. Method according to one of claims 1 to 7, characterized in that the ligand is chosen from the group comprising organophosphites, organophosphonites, organophosphinites, organophosphines mono or polydentates:

9. Method according to claim 8, characterized in that the organophosphorus ligand comprises at least one ionic group.

10. Method according to claim 9, characterized in that the ionic group present in the organophosphorus ligands is chosen from the group comprising the groups of anionic type belonging to the group comprising the anions sulfonate, phosphonate, phosphinite, carboxylate, sulfinate, or of type cationic belonging to the group comprising the cations guanidinium, ammonium, pyridinium, imidazolium, phosphonium, sulfonium.

11. Method according to one of claims 1 to 8, characterized in that the organophosphorus ligand is chosen from the group comprising tributylphosphine, dimethyl-n-octylphosphine, tricyclohexylphosphine, triphenylphosphine, tolylphosphine, tris (p- methoxyphenyl) phosphine, diplenylethylphosphine, dimethylphenylphosphine, 1, 4- bis-diphenylphosphinobutane, triethylphosphite, diphenylphosphite.

12. Method according to claim 9 or 10, characterized in that the organophosphorus ligand is chosen from the group comprising sodium triphenylphosphinomonometasulfonate), 2- (5-sodiocarboxyfuryl) diphenylphosphine, (3-sodiosulfinatophenyl) diphenylphosphine.

13. Method according to one of claims 2 to 12, characterized in that the slightly polar solvent is chosen from the family comprising saturated hydrocarbons chosen from the group comprising hexane, heptane, octane, toluene, and / or the ethers chosen from the group comprising diethyl ether, diisopropyiether, methylisobutyl ether.

14. Method according to one of the preceding claims, characterized in that the metallic element of the catalyst is nickel in the oxidation state 0 or 1.

15. Method according to one of the preceding claims, characterized in that the organic compound comprising at least one ethylenic unsaturation is an olefin, a diolefin comprising from 3 to 12 carbon atoms.

16. Method according to one of the preceding claims, characterized in that the organic compound comprising at least one ethylenic unsaturation is 1, 3-butadiene.

17. Method according to one of claims 1 to 14, characterized in that the organic compound to be hydrocyanated comprises at least one ethylenic unsaturation and a nitrile function.

18. The method of claim 17, characterized in that the compound comprising a nitrile function is chosen from the group comprising pentene-3-nitrile, pentene-4-nitrile.

19. Method according to one of claims 1 to 14, characterized in that it consists in isomerizing unsaturated nitrile compounds branched into linear nitrile compounds.

20. The method of claim 19, characterized in that the isomerization step is carried out in the absence of hydrogen cyanide.

21. Method according to one of claims 17 or 18, characterized in that the reaction is carried out in the presence of a Lewis acid.

22. Method according to claim 21, characterized in that the lewis acid is chosen from the group comprising the compounds of the elements of the groups Ib, Mb, Illa, lllb, IVa, IVb, Va, Vb, Vlb, Vllb and VIII of the Periodic Table of the Elements.

23. The method of claim 22, characterized in that said compounds are chosen from the group comprising halides, sulfates, sulfonates, carboxylates, phosphates, halogenosulfonates, perhaloalkylsulfonates chosen from the group comprising fluoroalkylsulfonates perfluoroalkylsulfonates, bis (perfluorakylsulfonyl) amides, tris (perfluoroalkylsulfonyl) methylides.

24. The method of claim 21, characterized in that the ionic liquid comprises an anion forming the Lewis acid.

5. Method according to one of the preceding claims, characterized in that the reaction is carried out at a temperature between 10 ° C and 200 ° C.